[asterisk-bugs] [Asterisk 0014815]: DTMF Appears to be broken from certain sources on asterisk 1.4.24 - double digit.

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=14815 
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Reported By:                geoff2010
Assigned To:                
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Project:                    Asterisk
Issue ID:                   14815
Category:                   Core/RTP
Reproducibility:            always
Severity:                   block
Priority:                   normal
Status:                     new
Target Version:             1.4.25
Asterisk Version:           1.4.24 
Regression:                 Yes 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-04-02 15:38 CDT
Last Modified:              2009-04-28 15:50 CDT
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Summary:                    DTMF Appears to be broken from certain sources on
asterisk 1.4.24 - double digit.
Description: 
I am having some trouble with 1.4.24.  This appears to be a regression
since 1.4.21.1 as I have just recently upgraded and started to experience
the problem.

When calling my asterisk box from a cell phone the system detects double
DTMF digits.  When calling from a landline or pure SIP device DTMF
detection works fine.  I have determined that the cell phone is sending the
RTP DTMF payload about 2x more than the other devices, but as far as I can
tell it should still be considered a single digit as per the RFC.

Attached are two TXT files of pcap exports which show the dump for a
working DTMF interaction, and one for a failure situation.

Please let me know if I can provide any further information.

Thanks,
Geoff
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Relationships       ID      Summary
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related to          0014460 Asterisk plays a continuous tone foreve...
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 (0103893) geoff2010 (reporter) - 2009-04-28 15:50
 http://bugs.digium.com/view.php?id=14815#c103893 
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@dimas - I believe the fact that the remote equipment is sending inband as
well as RFC2833 is not a problem.  My server is set to only do RFC2833, so
it will just ignore the inband audio.

The problem only occurs when the RFC2833 event is longer than 200ms
(approx).  When I generate DTMF data from my Aastra phone the event is
80ms, when I call from my land line into my asterisk over the PSTN the
event is 150ms.  Both of those scenarios work.  When I dial the asterisk
box from my cell phone through a Level3 DID the DTMF event is between 400ms
and 500ms... when the event is that long, the rfc2833 code will generate
multiple internal events for my single external event causing DTMF
duplication on read.

As a temporary workaround, I am preventing process_rfc2833() from ever
setting rtp->dtmfcount = 0.  I don't know what else that might break, but
it seems to have fixed the bug temporarily, and I have been able to
continue using 1.4.24 while waiting for a real fix.

Thanks! 

Issue History 
Date Modified    Username       Field                    Change               
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2009-04-28 15:50 geoff2010      Note Added: 0103893                          
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